Safety Mat Control Using CompactBlock Guard I/O and GuardLogix
Contents
1. Performance Data 23 Setting the Filter Timer Preset These timers also make sure that the channel inputs follow the channel outputs before the timers time out Before the output is turned OFF these timers must time out and the inputs must be in the same state This can only occur if one of the channels is shorted to 24V dc or GND or the channels are shorted to each other or a wire break occurs If the delay is only due to throughput RPI or period set HI and the inputs toggle after the filter timers time out but always remain in the opposite state then the filter timers will have timed out without turning off the output Set this preset based on how quickly the output must be set LO when the mat is stepped on Worst Case Reaction Time Based on Period Task RPI Filter Preset Typically one channel is HI and one LO When the mat is stepped on the channels short together and both inputs are HI since both have a path to the HI channel One channel now is HI at the input terminal and the output logically LO This starts the filter timer and when it times out since both inputs are HI the output is turned OFF Worst case the time it takes to occur is the sum of the A to E path as described below pria y C gt i A E gt A Input Module delay 16 ms on off delay filters B Input Connection Reaction Time Limit CTRL The Connection Reaction Time Limit is configured in R2. GompactBlock 8 inputs 8 Ouipots 24V0C Test Outputs Publication SAFETY AT011A EN P February 2008 Configure To support the hardware configuration shown above the following configuration was used The 1791DS IB8XOB8 module was added to the I O configuration under the 1756 DNB DeviceNet Bridge module as shown A RSLogix S000 SafetyMatLontrol in Safet y_Mat_linal_ May_1U_2006 ALD 1 754 L625 Fle Edt Wew Search Logk Communications Took Window Help alwa SB oie ol EDS Th alal EZA Paih AB_ETHIP1 192 168 0 107 Backplane D j 4 u LY The 1791DS IB8XOB8 module is configured as follows Module Definition X Gerez fa Revizion 1 1 Electronic Keping Exact Match Y Input Data safety Readback Input Status Pt Status Muting Test Output Output Data Combined Data Format Integer Cancel Help The options for Input Data are e Point Status Muting e Combined Status Muting e Point Status Muting Test Output Combined status lumps all eight input point status into a single bit and the same for the outputs Point Status provides an individual status bit for each I O point To obtain the Test Output status select the option with Test Output Publication SAFETY AT011A EN P February 2008 Publication SAFETY AT011A EN P February 2008 The options for Output Data are e Safety e Test e Combined Safety provides tags to control the 8 safe
3. Test Output Output Configuration PA not Used N Standard P Adl T ef Status Offline Cancel Apply Help The Output Configuration tab is shown below The options under Point Mode are e Safety e Safety Pulse Test e not used Outputs 2 and 7 are being used as indicators in the ladder code and thus are configured as safety outputs These indicators could be driven by standard output modules if safety outputs are in short supply lee Module Properties DeviceNetBridge 1791D5 IBSX0B3 A 1 1 General Connection Safety Module Info Input Configuration Test Output Output Configuration Output Error Latch Time 250 m Status Offline Cancel Apply Help Publication SAFETY AT011A EN P February 2008 14 Reaction to Faults Channel to Channel Short Actual Short or Stepping on Mat Reaction Detection Immediate Immediate After After Channel Start Fault Reaction Detection Toggle Toggle ATH oer W e s joj a e Short to 24V dc Immediate Immediate After After Channel Start Fault Reaction Detection Toggle Toggle E a a re s jo fef fm Short to 0V dc Immediate Immediate After After Start Fault Reaction Detection Toggle Toggle S a O a E 0 M aT Wire OFF Reaction Detection Immediate Immediate After After Start Fault Reaction Detection Toggle Toggle off off Yes w DA T a Yes aa i Other Fault Results
4. if there were matching node numbers on each DeviceNet network the SNN is used in combination with the DeviceNet node number to create a unique identifier e SNN 1 node 25 e SNN 2 node 25 There are two reasons for using a common SNN among all nodes on the subnet e First is documentation It is much easier to recall the SNNs of each node in case of replacement if they are all the same e Second is Auto Device Replacement ADR If you replace a DeviceNet node using ADR it will assume the SNN of the lowest node on the network If they are all the same it will assume the correct SNN 11 The ControlBus backplane that the GuardLogix controller sits on should have a unique SNN as well The ControlBus SNN in combination with its slot number creates its unique identifier The following screen capture shows that the SNN of the GuardLogix controller and the 1791DS module do not match in the ACD file im Module Properties DeviceNetBri ge 1791DS IBBXOBS A 1 1 g 0j x m General Connection Safety Module Info Input COMS Sbon Test Output Output Configuration Type 173105188058 8 Point 24VDC Sink Safety Inpul 8 Puirt 24 VDC Soure Safely Output 4 Controller Properties SatetyMatControl Miwa Fauls Date Time Advanced File Safety Memoy General SerialPort SystemProtocol UserProtocol Maio Fouts Chassis lype 1175647 7 Slot ControlLoga Chassis Cancel Arn He The default data was
5. mat Setting the Safety Task Period Set the Period based on the reaction time you require The lower the period the quicker the outputs will toggle and the quicker the reaction time None of the operational features of the application example are affected they just run slower as the period increases The Safety Task Period becomes the 1791 DS module output connection requested packet interval RPI Setting the RPI of 1791 DS Module The Requested Packet Interval RPI setting affects the operation of the safety mat application in the same way as the period Lower RPIs result in quicker reaction times But because the I O module RPI is asynchronous to the safety task if the RPI is set higher than the short circuit timer then you will likely see erroneous fault indications When the short circuit timer times out the fault is set The output will not necessarily go LO if the RPI is higher than the filter timer because if the inputs are diverse which they should normally be the filter timer 1s ignored Setting the Short Circuit Timer Preset These timers make sure that the channel inputs follow the channel outputs before the timers time out If the timers time out the appropriate fault indicator is energized We recommend setting this preset to the same value as the Filter Preset but no less than 75 ms If less than 75 ms then false indicators occur when the mat is stepped on due to how the faults are handled on the 1791 DS module
6. outputs supply 24V dc for the circuits They can be configured as described on the following page to automatically generate a pulse test Publication SAFETY AT011A EN P February 2008 Publication SAFETY AT011A EN P February 2008 Safety Mat Connections to I O Module CompactBlock 8 inputs 8 Oudpots NVOC Test Outputs Module Test Outputs lee Module Properties Safety _Dnet 1791D5 IB6Z0B86 A 1 1 General Connection Safety Module Info Input Configuration Test Output o Co Puce test z Not Used 3 44 4 3 Not Used Pulse testing Basics Both channel sources of 24V dc of any safety input are normally HI and thus the channel inputs are HI as well But if one source is pulsed LO then the corresponding channel input should go LO as well If the input follows the output LO then the pulse test passes But if the pulsed LO channel has another path to 24V dc such as a channel to channel short the input channel will not go LO and the pulse test will fail This is how the GuardLogix controller detects when the mat has been stepped on 1791DS DeviceNet Safety I O Modules are capable of performing on board pulse testing without any additional code in the GuardLogix controller However when the 1791DS modules detect a pulse test failure the inputs of the failed channels fault and remain faulted until the input channels go LO OV dc Since stepping on the mat does not set the channels LO th
7. If Then Mat is stepped on with a Wire OFF fault Output turns off immediately based on and in between toggles where wire came off Mat is off on input side of mat Outputs short together and generate a fault Wire is off on ouput side of mat Inputs both go HI and output turns off Publication SAFETY AT011A EN P February 2008 Programming 15 The safety mat channels are sourced by test outputs and monitored by safety inputs If all of these are LO then the output toggling has not started and is jumpstarted by setting the output for channel A HI Output Output Input Input Output SatetyMatChAcut SafetyMat ChBOQut SafetyMat ChAln SafetyMat ChBln Safety tat ChACut 0 m __ _ _ This rung sets the presets for the Short Circuit timers The Short Circuit timers provide time for the inputs to catch up to the output that is sourcing it This determines the amount of time to wait for the input to follow the output HI or LO They begin timing every time the test outputs are toggled If the inputs track to the same state as the Test Outputs before the timers time out then no faults are indicated The preset is entered in the Operator Mat UDT Le e EL Eo A M i LTD Dt a ta Pee il l l ad mili Operator Mat ShortCircutDetectionD elayT me 100 a ee Move Source SafetyMat ShortCircutDetectionDelay Time 100 Dest SatetyMat ChAShontToGNG PRE Internal Source Safetyhat ShortCircutDetectionDelay Time 100 Dest SatetyM
8. OH U0 Mal Stepped ON Fiter _irmer LH If the mat is stepped on the outputs therefore inputs as well are always in the same state toggling between HI and LO once again due to rung 7 The mat filter timer times out during this condition and turns off the output in the rung above input input Safety TE ChAln amend bn neh TON 13 Timer On Deloy EN ing Tires Mel _ Stepped ON Filer timer IN Preset 50 sepenan See Chain Danai Thain Accum 0 Publication SAFETY AT011A EN P February 2008 20 Publication SAFETY AT011A EN P February 2008 When a channel is shorted to GND both inputs go LO and stay LO This condition lets the mat filter timer to run incorrectly This counter can distinguish between the short to GND and stepping on the mat because it will not count if a short to GND fault occurs TLI ja fu flat _connirnetion 9oo99 U When the mat is stepped on for less than the Mat filter timer the counter still increments If this count is not cleared out the next short to GND could incorrectly be detected as stepping on the mat The mat filter timer enable bit clears the count when one steps off the mat to ensure that it is cleared out as quickly as possible hat_Stepped_ON_Filter_timer EN hiat _confinnation 15 gt esses If the Mat Stepped On timer times out and the Mat confirmation counter is greater than 1 then the mat has been stepped on A value of 2 or more is used because a short to 24V dc will c
9. SLogix 5000 1791DS Module Properties The Input Connection defaults to 4 x RPI C GuardLogix Delay The maximum delay for the filter timer to time out is Period Filter Timer Period round UP x Period Task Watchdog Publication SAFETY AT011A EN P February 2008 24 Publication SAFETY AT011A EN P February 2008 Example Filter Timer 50ms Period 15ms Task Watchdog 10ms 15 50 15 3 33 4 x 15 10 85ms The First Period accounts for the input just being missed because of the asynchronous Communications During Second Period start timer During Third Period time to 15 During Fourth Period time to 30 During Fifth Period time to 45 During Last Task Watchdog time to 50 and set output LO D Output Connection Reaction Time Limit The Connection Reaction Time Limit is configured in RSLogix5000 1791DS Module Properties The Output Connection defaults to 3 x RPI E Output Module Delay 6ms 20ms if using OW4 relay outputs Worst Case Reaction Time A B C D E Typical Reaction Time Based on Period Task RPI Filter Preset Typically one channel is HI and one LO When the mat is stepped on the channels short together and both inputs are HI since both have a path to the HI channel One channel now is HI at the input terminal and the output logically LO This starts the filter timer and when it times out since both inputs are HI the output is turned OFF Typi
10. Safety Application Example Safety Mat Control Using CompactBlock Guard I O and GuardLogix Integrated Safety Controller Safety Network enabled Example safety Rating Category 3 according to EN954 1 Tt O ar RNE natin EEE 1 GT et User Monna ON irssi 2 General Safety Information cccccccssescsssssssssssesssssssessessesessessseeees 3 EF tO WON a ee caaraeeanraneiepete waren 3 Example Bill OF Materials caicssisctsvccesvssiesiiincsacennatnansanctnbensndnsbavasioniennansayencss 8 SPUD ana HG rsen 8 Pa iE P E ET A E INEA O EEE Creer ee meen Tre rer 9 TALU 1 PEPEE E NET AT T T ETE ETT 15 ranamanct UMa eerren 23 POLENA We cerns resins EE EEE 26 Introduction This example shows how to wire configure and program a GuardLogix integrated safety controller with a CompactBlock Guard I O module for use with a dual channel safety mat and a dual channel e stop Features and Benefits e Uses programmable safety logic to control and monitor the status of a safety mat e Expandable as needed by adding additional safety inputs or outputs e Easier integration into Logix controllers and HMIs through standard DeviceNet control systems e Seamless communication of both safety and standard data using CIP Safety on DeviceNet networks Important User Information Publication SAFETY AT011A EN P February 2008 Solid state equipment has operational characteristics differing from those of electromechanical equipment Safety Guidelines for t
11. afety mat directly into a 1791DS Guard I O module and maintain at a minimum a CAT3 safety rating This document will describe the operational theory fault detection GuardLogix code and field wiring requirements The GuardLogix controller is programmed using RSLogix 5000 software You must be familiar with this software to use this document Safety Function ATTENTION A This application example assumes use of a dual channel safety mat It also assumes that the dual channels are shorted together whenever the safety mat is stepped on Unfortunately when this type of safety mat is wired directly into a 1791DS I O module there is simply no way to distinguish between an actual wiring short between the two channels and stepping onto the mat When either situation occurs a short is created between the channels For this reason Machine STOP must be the go to state when the mat is stepped on In other words the machine can never START due to a channel to channel field wiring short and this would be possible if stepping onto the mat caused the machine to start The GuardLogix controller must be capable of detecting the channel to channel short that is caused by stepping onto the mat The easiest method to detect this channel to channel short is to perform a pulse test This diagram shows the wiring for a typical pulse tested circuit The GuardLogix controller uses the 1791DS DeviceNet Safety CompactBlock Guard I O Module 1791DS test
12. at ChAShortToPVk PRE Internal Source SafetyhMat ShortCircutDetectionDelay Time 100 Dest SafetyMat ChBShortToGND PRE Source SafetyhMat ShortCircutDetectionDelay Time 100 Dest SatetyMat ChBShortToPyk PRE 100 This rung sets the presets for the Filter Timers which operate the same as the Short Circuit Timers The Filter Timers provide time for the inputs to catch up to the output sourcing it The filter determines the amount of time for the input to follow the output HI or LO These filters turn OFF the output if they time out If the input does not follow the output before the filter timer times out the safety Mat output must be turned off Publication SAFETY AT011A EN P February 2008 16 There are four timers one for each channel shorted to 24V dc and GND There 1s also a filter preset for the mat and someone must be on the mat until the filter timer times out to turn off the Mat output The preset is entered in the Operator Mat UDT The Short Circuit timers have nothing to do with turning OFF the output but are used for fault diagnostics If the Short Circuit timer is too low less than 75 ms it is possible to get incorrect diagnostic indicators It is therefore recommended the Short Circuit timers have a preset no less than 75 ms If a quicker response time is needed for safety shutdown when the mat is stepped on then the Filter presets can be set lower WSL a ee AL LA WLIW Operator Mat nputF iter T inne
13. at Chtin SotetyMat OKT x nA input ternal internal ma Cham SaotetyMet Chtin SatetyMat OKI Solely Mat OK2 k internal riernal SatetyMat OK2 TON Timer On Delay EN Timer SatetyMat AutoCrcouiResetTime CDN Preset D Accum 0 had bierra hiberred Cadpnd Soicyiot Orcuthicsct otebyelOrouwihieactUncthot Boteto OK heh Mal Ol a OnE nou Internal Sete Met ALoOrcuinesst Satetyiiet AvuboCircuireces Time DY Turn OFF the Mat output if both inputs are in the same state and the filter timers have expired This occurs when the outputs are toggled but only one of the inputs follows their respective outputs to the correct state The cause is likely that the mat was stepped on but it could also be a wiring short to 24V dc or GND Unless the filter timers were set very low it is very unlikely that network throughput caused the stop For example one of the channels was sent through over DeviceNet network but the other channel was not The Mat Stepped ON Filter is required to turn OFF output when the mat is stepped on because rung 7 causes the outputs to toggle in the same state and thus the filter timers do not time out because the inputs are tracking the outputs put input rernal internal EENT Safelybial h n SafelyMal Chin SafelyMal ChudOnToCitFiter TT SafelyMal ChACnTeCttFiter TT Satelyidal C11 i aL Ing kitana ternal Deter vel Chbin Daf Mai Caan IEA Eer 7 Lahey el CARON oon Er 1 j Inberral Saleiyhtal
14. ause the mat confirmation counter to increment to 1 When the mat is stepped on the counter increments continuously Inpart irant SafetyhiatCh ln SatetyMeat ChDln m Chalpad macy MeLOT Met Sicppod OM biker timer ON Mol Sicppod On IT Greater Than A Dame A Ma confirmation ADC i Amie A 1 Since there are separate Filter and Short Circuit timers it is possible that the filter timer drops out the output yet no fault condition is energized In these cases an undetectable fault is declared CUIA Faut Prereri Saleya Gd Satetyhimi FP Urnoetectabia Fauk if __ t 21 The last five rungs were added to differentiate between a short to GND and a wire OFF condition Both cause the channel input to go LO even when the channel output is HI Test Output status is required for this differentiation If a wire break occurs then the Test Output status remains HI If a short to GND occurs the Test Output status toggles at the Input Error Latch time rate A 5 byte connection is needed to obtain the Test Output status Combohodule Alo Testiulput Statue CTU 12 i Cound Up ZU Counter T2_teuk_counter Dh Preset yyyy ACCUM ComboModue A03Testiuipit Status TU 13 i Count Up ZU Counter TA faui _enunter Dh Preset 3999 AUT i Iripa Saretyiel Fauthieset T3_fauit_counter a RES T2_tauit_counter RES internal Satetyttet ChA Shor Teoh DH fl Mat
15. cally the time it takes to occur is the sum of the A to E path as described below n ajar E od D 25 A Input Module delay max 2 8ms B Input Connection Reaction Time Input RPI C GuardLogix Delay The maximum delay for the filter timer to time out is Period 2 Filter Timer Period round UP x Period Task Scan Time Example Filter Timer 50ms Period 15ms Task Watchdog 10ms Task Scan Time 5ms assumption 7 5 50 15 3 33 4 x 15 5 72 5ms The First Period accounts for the input just being missed because of the asynchronous Communications During Second Period start timer During Third Period time to 15 During Fourth Period time to 30 During Fifth Period time to 45 During Last Task Watchdog time to 50 and set output LO D Output Connection Reaction Time Output RPI Task Period E Output Module Dalay max 2 3ms Typical Reaction Time A B C D E Publication SAFETY AT011A EN P February 2008 26 Additional Resources For more information about the products used in this example refer to these resources Resource CompactBlock Safety I O Modules on DeviceNet Series 1791DS Installation Instructions publication 1791DS INO01 Guard I O DeviceNet Safety Modules User Manual publication 1791DS UM001 GuardLogix Controller Installation Instructions publication 1756 IN045 GuardLogix Controller Systems Safety Ref
16. ch vrine bresk Fi Fiqural tl Sure A TA adi tamer ACE fn naume O fn Fau Indata aRT Safety Mal ChA Shon ToGhOr aul Grealer Than 4 gt Fi Sure amp TA badi tamer ACE fn maune Fl fn Internal SafetyMat ChB Short ToGND OM EGU Mai chB wire_bresk 7 Fryual l Source A T3_faut_ counter Acc 0 Source A fl Fault Indication RT saletyMat Chisti KAA aul realer Tran A 8 Source A T3_foult_ counter AGC i Source B 0 End Publication SAFETY AT011A EN P February 2008 22 Setting the 1791 DS Input Error Latch Time Publication SAFETY AT011A EN P February 2008 We recommend that the Input Error Latch Time be set to zero Since the Faults are captured in software due to the output toggling there really is no reason to have to latch the fault If you do set the Input Error Latch time the following occurs e First it will have no effect on turning OFF the output in the event of a fault or stepping onto the mat The Latch time has no effect on the filter timer so the output will still go LO when the filter timer times out e Inthe event of a fault stepping onto mat or short circuit the fault cannot be reset during the Latch time e Inthe event of a channel to channel short stepping on mat or short to 24V dc it is likely that both the Short to Power and Short to GND indicators go HI e Ifthe mat is stepped on the mat stepped On indicator may not energize until the Latch timer times out And only if you are still on the
17. dules have test outputs capable of supporting this application All three 1791DS modules have four test outputs and so two remain for other uses Publication SAFETY AT011A EN P February 2008 Publication SAFETY AT011A EN P February 2008 The following faults are detected e Mat stepped on channel to channel short cannot differentiate between these e chA shorted to 24V dc e chB shorted to 24V dc e chA shorted to GND e chA wire break e chB shorted to GND e chB wire break e DeviceNet Fault not in this code easy to monitor Fault Exclusion Affecting Category Rating There is one combination of faults that could cause a dangerous failure of the safety mat in this application The three faults must occur in a particular order to create this dangerous situation The three faults are e channel short around the safety mat e wire OFF between either side of the safety mat and short e wire OFF between the other side of the safety mat and short First a channel short around the safety mat This does not change the circuit at all and is undetectable because the circuit is not broken when the mat is stepped on CompactBlock 8 inputs 8 Oulputs MVOC i iC ee ee Safety Mat Second wire OFF on either side of the safety mat Because of the initial short the wire OFF is undetectable When the mat is stepped on the channels still short together and there remains a path between the mat and in
18. e only way to generate a LO signal is to break the channels by using an inline switch The following diagram shows an inline switch that can be opened to generate the LO signals required to reset the 1791DS inputs in response to an on board pulse test fault Safety Mat with Switch _CompactBlock 8 inputs 8 Quipus MVDC This application example assumes that this additional inline switch will not be acceptable and presents an alternate solution This other solution will not use the on board configurable pulse testing for the reasons described above This application example shows how to generate the pulse test by toggling two 2 1971DS Test outputs HI and LO using ladder logic 1791DS 1791DS Test Safety Inputs Outputs Safety Mat Using simple ladder logic these outputs are toggled HI and LO causing the inputs to toggle HI and LO as well If the mat has not been stepped on the inputs should always be diverse one input HI and one input LO But when the mat is stepped on a channel to channel short occurs and the HI channel has a path to both inputs The software detects that the inputs are no longer diverse and drops out the safety mat output The advantage of using ladder logic rather than on board pulse testing is that any 1791DS faults shorts to 24V dc shorts to V dc channel to channel short are temporary and are automatically reset when the fault is cleared for example stepping off the mat All three 1791DS mo
19. erence Manual publication 1756 RM093 GuardLogix Controllers User Manual publication 1756 UM020 Safety Mats Overview publication 440F CA500 MatGuard Mats publication 440F CA501 Product Certifications website Description Provides instructions for installing your DeviceNet Safety I O Module Provides information for using the Guard I O DeviceNet Safety Module Provides instructions for installing your GuardLogix Controller Provides safety guidelines for using your GuardLogix Controller Provides information for using your GuardLogix Controller Provides general information about MatGuard mats 115 Provides MatGuard Mat specifications Provides declarations of conformity http ab com certificates and other certification details Industrial Automation Wiring and Grounding Guidelines publication 1770 4 1 Provides general guidelines for installing a Rockwell Automation industrial system You can view or download publications at http literature rockwellautomation com To order paper copies of technical documentation contact your local Rockwell Automation distributor or sales representative Allen Bradley CompactBlock Guard ControlLogix GuardLogix MatGuard Minotaur Safety Rockwell Automation and RSLogix 5000 are trademarks of Rockwell Automation Inc Trademarks not belonging to Rockwell Automation are property of their respective companies www rockwellautomation com Power Control a
20. he Application Installation and Maintenance of Solid State Controls publication SGI 1 1 available from your local Rockwell Automation sales office or online at http literature rockwellautomation com describes some important differences between solid state equipment and hard wired electromechanical devices Because of this difference and also because of the wide variety of uses for solid state equipment all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable In no event will Rockwell Automation Inc be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment The examples and diagrams in this manual are included solely for illustrative purposes Because of the many variables and requirements associated with any particular installation Rockwell Automation Inc cannot assume responsibility or liability for actual use based on the examples and diagrams No patent liability is assumed by Rockwell Automation Inc with respect to use of information circuits equipment or software described in this manual Reproduction of the contents of this manual in whole or in part without written permission of Rockwell Automation Inc is prohibited Throughout this manual when necessary we use notes to make you aware of safety considerations Identifies information about practices or circumstances tha
21. it reset push buttons They are set to Standard because reset buttons are not safety inputs Inputs 0 and 1 were used for the safety mat inputs Since these are safety inputs they are configured as Safety inputs They were not configured as Safety Pulse Test because we are not using the on board pulse testing feature for the reasons described at the beginning of this document ee Module Properties DeviceNetBridge 1791D5 IBEX0B3 A 1 1 General Connection Satety Module Info Input Configuration Test Output Output Configuration Point Point Operation o Test Input Delay Time m Delay Time mE Point Discrepancy Point Mode Ource Type Tre aai Off On On Ott LT of om ERE EE Standard J lNone e oj o o4 E mse lore o ES 5 None H oH o2 Input Error Latch Time 4 mg Status Offline Cancel Apply Help 13 The Test Output configuration is shown below Test Outputs 2 and 3 are being used as the source for the safety mat channels and are set to Standard Even though they are not Safe outputs when used in this configuration the redundancy two channels and diagnostics alternating the outputs makes it possible to detect all wiring faults using ladder logic allow the channels to achieve at least a Category 3 rating per EN 954 1 odule Properties DeviceNetBridge fa le Module P ties DeviceNetBridge 1791D5 IBSX0B6 A 1 1 General Connection Safety Module Info Input Configuration
22. nd Information Solutions Headquarters Americas Rockwell Automation 1201 South Second Street Milwaukee WI 53204 2496 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Europe Middle East Africa Rockwell Automation Vorstlaan Boulevard du Souverain 36 1170 Brussels Belgium Tel 32 2 663 0600 Fax 32 2 663 0640 Asia Pacific Rockwell Automation Level 14 Core F Cyberport 3 100 Cyberport Road Hong Kong Tel 852 2887 4788 Fax 852 2508 1846 Publication SAFETY AT011A EN P February 2008 Copyright 2008 Rockwell Automation Inc All rights reserved Printed in U S
23. pping onto the mat and a channel to channel short So the Mat Stepped on LED could actually be the indication for a channel to channel short Input internal Faut Present Safety FautResct SafctyMat FoutResctOncShot SotetyMat FP 8 Jf ons u Fault Indication Satetytet ChAShotToGNor aut Faul budicabion SatetyMat ChaShortToPyyRF aur Fault indication Satetyitat OKBN NATI AGND ALE Fault Indication SatetyMat ChBShortToPVVRF aut Met_chA_wire_break Met_chB_wire_break Mat_Stepped_on_led Latch the Fault indicators and Fault Present when the Fault timers expire The Short to GND faults have been removed from this rung and used later because they are broken down to a more granular level internal Faut incicstion Faut Present SafetyMat ChAShcetToPAR DN SafetyMat ChAShortTolVAF aut Safety FP L L kirsid Fadl idiali SatetyatChBShorToPAR Ohl SatetyMatChBEShonToPARF aut Internal SafetyMat ChAShoatToGNod DN interne satetyMat Chbtshort oGND DN bta _Sleppirsi_ Cvi Mial _Siepprsi_on ied Eem 19 Rungs 10 and 11 allow the restart of the Mat output if there are not faults Restart requires that the inputs toggle through both safe states 1 0 and 0 1 If using Auto Reset wait 50 ms after toggling through the safe states before restarting the output If using Manual Reset the Circuit Reset must be set HI after toggling through the safe states input ingut internal SalctyMat Cham SatetyM
24. put oe e r S E E __ CompactBlock 8 inputs 6 Quiputs 24VDC Third wire OFF on the other side of the safety mat After this third fault there is a dangerous failure of the safety mat If the mat is stepped on there is no channel to channel short between the two channels and thus the safety mat output will remain energized Publication SAFETY AT011A EN P February 2008 If no action is taken to detect these faults as they occur then this safety mat application will have to be rated to CAT3 One possible method to detect this condition is to place a switch on either side of the mat After the first fault opening this switch will not drop out the input thus detecting the short around the mat This example meets the requirements of Category 3 according to EN954 1 Example Bill of Material This functional safety example uses these components Catalog Number Quantit 1756 L62S 1 1756 LSP 1 1791DS IB8XOB8 CompactBlock Guard I O module on DeviceNet 1 8 safety inputs 4 pulse test standard outputs 8 safety outputs 1606 SL 1 1756 A10 B 1756 PA72 1756 ENBT 1756 DNB 440F M2010BYNN 39 4 x 19 7 MatGuard safety mat ee d Setup and Wiring For detailed information on installing and wiring refer to the product manuals listed in the Additional Resources on page 26 System Overview Guard O Safety Mat Wiring The following diagram shows how the safety mat is wired using two test outputs ___
25. rasei Yi ACCU Cutpa st npu Saleya ChB A Saletykial Chet _ ai Delay Tiner Satetyhad ChBOnTootir bar el pened 15 The next two rungs keep the outputs toggling If A output goes HI then A input should follow When it does set A output LO and set B output HI When B output goes HI then B input should follow When it does set B output LO and set A output HI and so on Safetyiat crd Rea ROA 5 k Li Output Saleya ChFC Stet 0 Ch ri This rung keeps everything working properly when a fault occurs It allows detection of a channel short to 24V dc and it also allows the non faulted channel to keep toggling while the faulted channel times out This rung also allows detection of a channel to channel short Without it only channel B will incorrectly be detected as faulted simply due to the order of the rungs With this rung both channels toggle together which can be easily monitored This rung does nothing if a single channel shorts to GND When that occurs the toggling simply stops and the correct channel fault is detected Input Ingat ut put Seafelpetel Chal Safelyhial ChB Safelybtal Chaco Publication SAFETY AT011A EN P February 2008 18 Publication SAFETY AT011A EN P February 2008 Clear all fault indicators on the rising edge of the fault reset If the fault still exists the next run sets the fault again Once again this program cannot distinguish between ste
26. t can cause an explosion in a hazardous environment which may lead to personal injury or death property damage or economic loss Identifies information that is critical for successful IMPORTAN application and understanding of the product ATTENTION Identifies information about practices or circumstances that can lead to personal injury or death property damage or economic loss Attentions help you identify a hazard avoid a hazard and recognize the consequence SHOCK HAZARD Labels may be on or inside the equipment for example a drive or motor to alert people that dangerous voltage may be present BURN HAZARD Labels may be on or inside the equipment for example a drive or motor to alert people that surfaces may reach dangerous temperatures EOE A ronan aon A A Description General Safety Information IMPORTANT This application example is for advanced users and assumes that you are trained and experienced in safety system requirements A risk assessment should be performed to make sure all addressed The risk assessment may require additional circuitry to reduce the risk to a tolerable level Safety circuits must take into consideration safety distance calculations which are not part of the scope of this document task and hazard combinations have been identified and Contact Rockwell Automation to find out more about our safety risk assessment services This document details how to interface a s
27. ty outputs Test provides tags to control the 4 test outputs Combined provides 12 tags for 8 safety outputs and 4 test outputs Since we are using the test outputs select Combined The only choice for Data Format is Integer lel Module Properties DeviceNetBridge 1791D5 IBSZ0B6 A 1 1 General Connection Safety Module Info Input Configuration Test Output Output Configuration Type TFSI 0S5 IBSHOBS 8 Point 42W DC Sink Safety Input 5 Point 24 YOC Source Safety Output Vendor Allen Bradley Parent DeviceN ath nidge Hame Combat odule Node E Description 7 Safety Network 30CD_O31F_7A73_ eee SOCD_OSIF_L AFS a El 3 16 2006 9 33 14 611 AM Module Definition Seres A Change Revisio 1 1 Electronic Keping Exact Match Input Data Safety Readback Input Status Pt Status Muting Test Output Output Data Combined Data Format Integer Status Offline Cancel Apply Help The only other options under the General tab are DeviceNet Node number and Safety Network Number The DeviceNet Node number is set using the rotary dial switches on the 1791DS module There is much confusion regarding the Safety Network Number When the Safety Network Number SNN is used all the devices on any safety network should have the same SNN If there are two DNBs and thus twoDeviceNet safety networks each network should have a unique SNN This provides a level of safety so that
28. used in the Connection and Safety tabs shown below They should be changed based on the throughput requirements of your system lee Module Properties Safety _Dnet 1791D5 IB33066 A 1 1 General Connection Safety Module Info Input Configuration Test Output Output Configuration Major Faut On Controller lf Connection Fails While in Run Mode Requested Packet Interval RPD me Connection Safely np z Safety Outpu Publication SAFETY AT011A EN P February 2008 12 Publication SAFETY AT011A EN P February 2008 E Module Properties Safety_Dnet 1791D5 IB620B8 A 1 1 General Connection Safety Module Info Input Configuration Test Output Output Configuration Connection Requested Packet Connection Reaction Max Observed A Type Interval RPI m Time Limit m Metwork Delay m Saty npa wao oj eal et Safety oupa 10 w nme l Rese Configuration Ownership Local Reset Ownership Configuration Signature ID B351 cg Hex Copy Date fi 1 08 2005 Time 09 06 15 4M 424 ms Status Running OK Cancel Apply Help The Input Configuration tab is shown below There are three choices under Point Mode e Standard input circuits not tested internally e Safety input circuits tested internally e Safety Pulse Test input circuits tested internally and wired to a Test Source for pulse testing Inputs 4 and 5 were used for the Fault reset and Circu
29. v1 mM mmr shard ha ey Leek ire uki a ee TEN l i iT ies ui a ee DO OT ee eire inna hternal MOY huve Source Safety Meat InpulFiter Tine 50 Dest Satetyiat ChAOTITOONF Iter PRE Source SafetyMeat InpulFiter Tine 50 Dest Salelyttel ChAOnTuOiFiler PRE Source Safety Meat InpulFiter Time 50 Dest SofctyMet ChBOffToOnFitcr PRE 50 hternal Source SafetyMat InpulFiter Time 50 Desi SafetyMst_ChBOnToOtiFiter PRE 50 1OY Move Source SafetyMat InpulFiter Time 50 Dest Mal_Sleppet_ON_Filler_linies PRE 50 These are the Short Circuit and Filter timers for channel A They begin running if the Output is HI and the input LO or vice versa Quiput input Internal Safelyitel ChA Salfelytlel ChA Timer On Delay Ime Satetyiat hashort on Precast 100 Accum 15 htermnmal TOW Timer On Delay Timer Safety Chao Toor iter Preset il Sua 15 Culpa kiput Internal Safety ChAcut Safetyot Chin TON J Timer On Delay Times Ralelybial ChA Sho oP Presa in Acum ih Timer On Delay leer Satetymst Chan oUt itar Presst 5U Accum ut Publication SAFETY AT011A EN P February 2008 17 These are the Short Circuit and Filter timers for channel B Output input Infernal SatetyMat ChBQut SatetyMat Chen TON 4 rH Timer Accum Timer On Delany EN Teter Tater Ma CABO TOOnF aber DM P
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